can the 18 round dish be used at all any more

Yes, it can still be used but you will no longer get any SD local channels as those are being shut down. If you wish to continue to be able to view local channels please purchase an SL3 SWM satellite dish with an 2 inch tripod pole to put the dish on. You’d also need a 21V power inserter to power the SWM LNB on the HD slimline dish.

If you wish to continue using the 18 inch dish (you won’t get any locals with this dish) the dish is aimed as always toward satellite 101. Also, make sure the H24 has the proper dish setting for an 18 inch dish. This would be by going to Menu, Settings & Help, Settings, Satellite, Repeat Satellite Setup, and press the (-) DASH button. Then, set the switch type as Multiswitch and the satellite as 18 Inch. 

I moved receiver from Texas location to rv in California. Texas dish is SL3 LNB…..SWM. In California I’m using 18” round dish. Switch type-multi switch. Changed settings. Put on b band converter. Dish is level using correct coordinates. No go. You I left same location in August and it was working. Used receiver in Texas until now. I wonder if all my settings are correct. Any thoughts?

You have to rerun sat setup and select mutiswitch first then select 18" round.  DTV is shutting down the MPEG2 SD channels and all local channels on the 101 sat but should continue broadcasting channels in MPEG4 but you need an MPEG4 receiver to watch them.

Still no luck

You don't need the BBC since you aren't connected to an hd dish anyway. You could try it without it.